1. Department of Economics and Department of Biological Sciences, Stanford University, Stanford, California 94305, Faculty of Economics and Politics, Cambridge University, Cambridge CB3 9DD U.K., Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544-1002, The Beijer Institute, The Royal Swedish Academy of Science, Box 50005, S-104 05 Stockholm, Sweden, Department of Economics, Littauer 308, Harvard University, Cambridge, Massachusetts 02138, Resources for the...